The most commonly reported condition in the U.S., genital Chlamydia trachomatis cases continue to climb: in 2006, over 1 million cases were reported (case rate: 347.8 cases per 100,000 population). Other assessments also indicate that the chlamydia disease burden is substantial. Among women aged 15-24 years attending family planning clinics, the 2006 state-specific median positivity rate was 6.7%. In adult corrections facilities, the 2006 positivity rate among women <20 years was almost 20%; among men of the same age, the rate was over 10%. Persistently high chlamydia rates may be due to better detection, reporting, screening, and true disease burden.